Method of recovering ammonia from coal-gases and the like.



J. A. ROELOFSEN. METHOD OF RECOVERING AMMONIA PROM COAL GASES AND THELIKE. APPLICATION FILED APR. 19,1910.

969,907. Patented Sept.13,1910.

UNITED STATES PATENT OFFICE.

JAN ADOLF ROELOFSEN, or MIDDLESBBOUGH, E GLAND, ASSIG-NOR TO THEAorist:- GESELLSCHAFT rune KOHLENDESTILLATION, OF DUSSELDORF, GERMANY, Acon- PORATION 0F GERMANY.

METHOD OF RECOVE'RING- AMMONIA FROM GOAL-GAQsES AND LIKE.

Specification 01' Letters Patent. Patented Sept. 13, 1910.

Application filed April 19, 1910.

Serial No. 556,402.

To all whom it may concern:

Be it known that 1, JAN AooLr RoELor- SEN, a subject of the King ofGreat Britain, residing at Southcote, lambridge Road, Middlesbrough, inthe county of York, Eng1and,ha.ve invented certain new and usefulImprovements in Methods of Recovering Ammonia from Coal-Gases and theLike, of which the following is a specification.

One of the objects of this invention is to recover ammonia from gases asa salt, preferably sulfate, by means of a smaller and more economicalinstallation than in the prior processes previously known, and withoutthe troublesome reheating of the gases of carbonization which, ifthesegases are subsequently treated for the extraction of benzol requireto be cooled afterward; further, to prevent the contamination of themarketable ammonium salt by tar and the like, and the contamination ofthe gases of carbonization, from which thetar and-ammonia have beenseparated, by obnoxious gaseous ingredients, which render these gasesinapplicable for illuminating or power purposes, and lower theircalorific value unless purified by expensive processes.

.A further object is to'greatly reduce the amount of obnoxious. efiiuentproduced, and finally, toeflect economies by using hot air, hot.products of combustion, or other hot neutral gases, which do notpermanently combine with ammonia, in place of steam, in

the operation of the ammonia still,--and to maintain the concentrationof the acid solu- -tion of the ammonium salts by superheating the vaporsobtained fromthe ammonia still before they enter the acid solution.

aqueous vapor containing most of the ammoniac'al and other fixed salts,as well as some free ammonia; these oily and aqueous condensates arecollected and separated by gravity in tank 3. The gases ofcarbonization, after hf1 g thus been cooled, pass through a gas-blower 1and a Plouze tarextractor 5, which separates the residual tarry vapor,and without being reheated, are conducted through pipe 6 into aleadlined saturator 7 J The condensed ammonical liquor from tank 3 isdelivered, by means of pump 8, through pipe 9 into ammonia still 10, analkali, such as lime, being also introduced, and into which still, theblower 11 forces, through pipe 12 and superheater 15, a current of hotair, hot products of combustion, or any other hot neutral gases which donot permanently combine with ammonia. The ammonia thus liberated passesthrough pipe 13 and superheater' 15 into saturator 7.

The saturator 7 is divided into two compartments by means of thediaphragm 16,

which dips into the acid solution of ammonium salts contained in thesaturator 7 The gases of carbonization enter into one of thesecompartments through the perforated end of pipe 6, pass up through theacid solu-- tion, and leave the-saturator, after having thus been. freedfrom residual ammonia, by

-means of pipe l7. 'T'he vapors from the ammonia still 10, enter theother compartment of the saturator 7, through the perforated end of pipe13. The contained ammonia is thereby absorbed, while the aqueous vaporand noxious gases which may contain hydrogen sulfid and other gaseoussulfur compounds, hydrocyanic-acid, carbonic acid and traces ofhydrochloric acid, pass out of the satur'ator through pipe 18; theeffect of the superheating of the vapors coming from the ammonia still10 being to prevent condensation of water in the saturator 7 and therebya lowering of the concentration of the acid solution which would reventthe ammonium: salt from separating 1n the solid dpreferably am in formsthe subject-matter of my copen ding a plication, Serial-No. 556,401.Icaim:- 1-

1. The method of recovering ammonium salts from gases of carboniza'tion,which comprises cooling the gases to separate-there from the tarrymatters and condensing the aqueous vapor containing most of the com:bined aini'noniacal products and a ortion of the free ammonia,distilling said amnioniacal condensate, simultaneously introducing saidgases and the vapors of distillation independently into a single acidsolution of ammonium salts, and separately leading oil? the gases ofcarhonization and the noxious gaseous COIHPOHQlltS of the vapors ofdistillation emerging from said solution.

2. The method of weovering anunonium salts from gases of carl'ionimtion,which coup prises cooling the gases to separate therefrom the tarrymatters and condensing the aqueous vapor containing most of the fixedaniinoniacal compoui'nls and a portion of the volatile ammoniacalcompounds, introducing hot neutral gases which do not permanentlycombine with an'nnonia, into a mixture of the aminoniacal condensateobtained in the cooling of the gases, with an alkali, i 'or the purposeof liberating the ammonia there-- from, and conducting the resultingammoniacal gas mixture to a saturation bath.

3. The method of recovering ammonium salts from gases of carbonization,which comprises cooling the gases to separate therefrom an ammoniacalcondensate comprising the tarry matters and condensingthe aqueous vaporcontaining most of the fixed ammoniacal compounds and a portion of thevolatile ammoniacal compounds, introducing hot neutral gases which donot p -:rmanentl.y

combine with ammonia, into a mixture of said ammoniacal condensate withan alkali, for the purpose of liberating the ammonia therefrom,simultaneously introducing said. gases and the vapors of distillationindependently into a single acid solution of an1 monium salts, andseparately leading off the gases of caihonination and the noxiousgaseous .:omponents of the vapors of dis tillatioi'i emerging from saidsolution.

4-. The method of recovering ammonium salts from gases which comprisesthe superheating of the vapors obtained from the distillation ofammoniacal condensate by indirect application of heat from hot neutralgases, and conduotin g the superheated vapors thus formed into an acidsolution of ammonium saits for'the purpose of preventing condensation ofsaid vapors and. maintaining the coi'icentratioir of said acid solutionso that solid amntionium salts will separate therefrom.

In testimony whereof I affix my signature in'presence of two witnessesJAN ADOLF R0 ELOFSENI \Vitnesses Row. G. REYNOLDS, EUGENE G BRoWN.

